More than three decades after the passage of Proposition 13, California voters strongly support rewriting one aspect of the landmark initiative that some commercial property owners have used to keep their taxes low, a new Field Poll shows.

By 69 percent to 17 percent, poll respondents said business property should be reassessed whenever it is sold or transferred - the same rule that applies to residential property.

Prop. 13, which voters approved in 1978, set 1975 as the base year for residential and commercial assessments and limited property-tax increases to 2 percent a year. When properties are sold, they are reassessed and annual taxes are set at 1 percent of their value.

The result is that owners who have held their property for years typically pay much less in taxes than their neighbors. But because of complexities in the way businesses are sold, commercial properties - unlike residences - are not always reassessed.

The poll showed strong bipartisan backing for changing that. Seventy-one percent of Democrats and independents said Prop. 13 should be altered to make sure commercial properties are reassessed whenever they change hands, as did 64 percent of Republicans, the poll said.

Field Poll Director Mark DiCamillo noted that such a change would be different from creating "split rolls" that would tax residential and commercial properties at different rates - a proposal that has been floated by some liberals in recent years and has gone nowhere.

The poll's findings show that voters would back "dealing with a particular quirk of the law, in which it appears that many business and commercial properties are able to skirt reassessments" and keep their taxes low, DiCamillo said.

Overall, the poll found that a plurality of voters, 49 percent, said they generally supported changing parts of Prop. 13, while 34 percent were opposed and 17 percent were undecided.

DiCamillo said support for Prop. 13 is still strong, but that groups interested in chipping away at the initiative may find some solace in the poll.

Making sure business properties are reassessed when they're sold "would be one way of opening the door," he said. "If you're trying to do that through split roll, that would be more contentious and you would get push-back from Republicans."

The survey, taken among 1,000 registered voters in California, was conducted from March 18 to April 5. The margin of error was 3.2 percentage points.